Method of treating metal structures to prevent subsequent change in form.



J, 0. HEINZE, JR. METHOD OF TREATING METAL STRUGTURBS TO PREVENTSUBSBQUENT CHANGE IN FORM. APPLIOATION FILED APR. 9, 1912.

l wgggg Patented Mar. 16, 1915.

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JOHN O. HEINZE, 3B, 013 DETROIT, MICHIGAN, ASSIGNOR T0 GENERAL MOTORSCOMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

METHOD OF TREATING METAL STRUCTURES TO PREVENT SUBSEQUENT CHANGE INFORM. I

Specification of Letters Eatent.

Patented Mar. 16, 1915.

Application filed April 9, 1912. Serial No. 689,603.

To all whom it may concern:

Be it known that I, J 01m 0. HEINZE, Jr., a citizen of the UnitedStatesof America, residing at Detroit, in the county of Vayne and Stateof Michigan, have invented certain new and useful Improvements inMethods of Treating Metal Structures to Prevent Subsequent. Change inForm, of which the following is a specification, reference being hadtherein to the accompanying drawings.

The invention relates to the manufacture of machined parts where it isnecessary to the proper operation to maintain an exact form. such forinstance as the pistons and cylinders of engines. Such structures areusually formed of cast metal, and as an incident to the cooling moltenmetal during the casing process. unequal stresses are set up in themetal. These stresses may be partially relieved by the removal of thescale in roughing out the structure, but experience has demonstratedthat until the metal is subjected to work analogous to that which itperforms in the complete structure, these stresses are not entirelyequalized. Asa consequence the pistons may be ground or otherwisefashioned to exactly fit the cylinder, but after the machine has been inoperation for a short time the form will change.

My invention is designed to overcome this difliculty by magneticallyagitating the molecules of the metal before the casting is fashioned,thereby equalizing the stresses and preventing subsequent change inform.

My method of treatment may be carried out in various ways, but asshown,

In the draw1ngs,F1gure 1 1s a sectional elevation of one form ofapparatus: Fig.2

is a horizontal section therethrough; and Fig. 3 1s a diagrammatic viewshowing the magnetic connections.

A. is a core of laminated magnetic metal which is preferably in the formof a continuous ring.

B is a helix or solenoid which is insertible within the ring A and whichis adapted to receive the metal to be treated.

As shown, the structure which is treated is a piston C the length ofwhich corresponds to the distance between the opposite poles D and E ofthe ringA, whereby a complete magnetic circuit will be formed when thehelix or solenoid B is energized.

The process of treatmentis to first insert the casting G into the helixB, then to place said helix and core within the ring A, after which analternating electric current is passed through the helix or solenoid.This will produce magnetic vibrations within the metal C which willrelieve the condition of unequal stress and permit the metal to asthecasting to a treatment after the rough ing out out has been taken, butbefore the grinding or other finishing operation, and in some instancesit may be desirable to subject the metal to a plurality of treatments,first in the rough and then after each machine cut. v

For convenience in manipulation the helix B is provided with a handle Fby which it may be inserted or withdrawn and the electric connections tothe circuit G including the alternating current generator H, may be comleted through this handle.

What I-claim asmy invention is:

1. The process" of treating metal to equalize molecular stresses thereinwhich consists in subjecting the same at normal temperature tomagneticfluctuations.

sume a form which will be permanently rel 2. The process of treatingmetal at normal temperature to equalize molecular stresses therein whichconsists in including the metal to be treated within a magnetic circuitand producing magnetic fluctuations in said circuit. v

3. The process of treating metal at normal temperature to equalizemolecular stresses therein which consists in placing the metal to betreated in a magnetic circuit and electric current through the helix toproduce corresponding magnetic fluctuations in the metal treated.

5. The method of treating solid'metal to alter its molecular structure,consisting in temporarily subjecting it to the action of the magneticfield of an alternating current. v

6. The method of treating solid metal to alter its molecular structure,consisting in placing said metal adjacent to a conductor carrying analternating current, subjecting it to the action of the magnetic fieldof said current until the desired result is obtained, and 'then removingit therefrom.

7. The method of treating solid metal to alter its molecular structure,consisting in placing it Within a coil, passing an alternating currentthrough said coil, and subjecting the metal to the action of themagnetic field of said alternating current until the desired effect isobtained, and then removing it therefrom.

In testimony whereof I afiix my signature in presence of two Witnesses.-

JOHN O. HEINZE, JR, Witnesses:

JAMES P. BARRY, Dnnnnnr COLLINS.

